Shock absorbing mechanism for railway cars

ABSTRACT

A RAILWAY CAR INCLUDES A FRAME STRUCTURE SLIDABLY SUPPORTING A CENTER SILL CARRYING COUPLER MEANS. SHOCK ABSORBING MECHANISM INCLUDES A CYLINDER AND A PISTON SLIDABLE THEREIN. A PAIR OF KEYS ARE CONNECTED WITH THE CYLINDER AND PISTION, THE KEYS EACH HAVING A LOST MOTION CONNECTION WITH THE CENTER SILL AND THE FRAME STRUCTURE. THE CYLINDER IS DIVIDED INTO A LARGE CHAMBER AND A SMALL CHAMBER INTERCONNECTED BY A PASSAGE HAVING A CHECK VALVE THEREIN. A SECOND PASSAGE PROVIDES COMMUNICATION BETWEEN THE LARGE AND SMALL CHAMBERS AND HAS AN ADJUSTABLE METERING MENS THEREIN. THE CHAMBERS ARE FILLED WITH AIR BY MEANS OF A DIFFERENTIAL AIR INLET VALVE WHICH IS CONTINUOUSLY CONNECTED WITH A SOURCE OF AIR PRESSURE.

p 0. 1971 E. o. LUNDE 3,606,031

SHOCK ABSORBING MECHANISM FOR RAILWAY CARS Filed Sept. 16, 1969 2 Sheets-Sheet 1 I02 96 no 1 1 I08 \\\\\r\ rz 70 I00 l8 In F I G. 4.

FIG .6.

INVINTOI EINAR O. LUNDE Sept. 20, 1971 5, LUNDE 3,606,031

SKOCK ABSORBING IECHANISI FOR RAILWAY CARS Filed Sept. 16, 1969 2 Sheets-Sheet 2 ll H I O Q 3| I i N 4 O I no u I u I I 5 i v y In I I 5 N 5 8 m Q I INVENTOI EINAR O. LUNDE Patented Sept. 20, 1971 US. Cl. 213-8 7 Claims ABSTRACT OF THE DISCLOSURE A railway car includes a frame structure slidably supporting a center sill carrying coupler means. Shock absorbing mechanism includes a cylinder and a piston slidable therein. A pair of keys are connected with the cylinder and piston, the keys each having a lost motion connection with the center sill and the frame structure. The cylinder is divided into a large chamber and a small chamber interconnected by a passage having a check valve therein. A second passage provides communication between the large and small chambers and has an adjustable metering means therein. The chambers are filled with air by means of a differential air inlet valve which is continuously connected with a source of air pressure.

BACKGROUND OF THE INVENTION The present invention relates to railway cars of the type having a floating or slidable center sill which is supported by the frame structure of the car for slidable movement longitudinally of the car. Conventional coupler means are carried at opposite ends of the center sill.

Shock absorbing mechanism is provided for cushioning movement of the center sill with respect to the frame structure. Such shock absorbing mechanism is necessary to absorb the kinetic energy arising from loads on the coupler means carried by the center sill imposed by cooperating coupler means on another railway car.

Various shock absorbing mechanisms have been provided in the prior art, but such prior art constructions are of complex and expensive construction and require excessive maintenance.

Where the shock absorbing mechanism includes a fluid shock absorbing mechanism it is often diflicult to maintain the proper operating characteristics due to leakage of fluid from the structure.

SUMMARY OF THE INVENTION In the present invention, a center sill is slidably supported by the frame structure of the railway car, and the shock absorbing mechanism includes a cylinder and a piston. A pair of keys are provided, one key being connected with the cylinder and the other key being connected with the piston. Each of these keys has a sliding lost motion connection with the center sill and frame structure.

The cylinder is divided into a large and a small chamber which are interconnected by a first passage having a check valve therein permitting flow of fluid from the large chamber into the small chamber but preventing reverse flow of fluid from the small chamber to the large chamber. A second passage interconnects the large and small chambers and permits flow of fluid from the second chamber to the first chamber, such flow of fluid being controlled by an adjustable metering means in the form of a needle valve.

The fluid disposed in the shock absorbing mechanism preferably is air, the air being introduced through a differential type air inlet valve which is continuously connected with a source of air on the railway car such as the air brake supply.

The differential air inlet valve automatically admits air into the chambers of the shock absorbing mechanism until suflicient pressure is built up within the chambers thereof to close the valve. The valve will automatically reopen if the pressure within the chambers drops below the pressure at which the differential valve closed whereby the air inlet valve only opens to admit air in the event a certain amount of air pressure is lost within the chambers due to leakage.

The construction of the present invention is advan tageous since it is relatively simple and inexpensive and is inherently quite trouble free. The pressure in the chambers of the shock absorbing mechanism will be maintained at all times, and there will be no hunting in the air inlet valve because the unit closing pressure is greater than the pressure at which the valve opens.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic plan of a railway car incorporating the shock absorbing mechanism of the present invention;

FIG. 2 is an enlarged view partly in sections of a portion of the structure shown in FIG. 1;

FIG. 3 is a side view partly broken away and in section showing certain details of construction of the cylinder and piston of the shock absorbing mechanism shown in FIG. 2;

FIG. 4 is an enlarged view of the air inlet valve shown in FIG. 3;

FIG. 5 is a sectional view taken substantially along line 55 of FIG. 3 looking in the direction of the arrows; and

FIG. 6 is a sectional view taken substantially along line 66 of FIG. 3 looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, as seen in FIG. 1 a railway car includes a typical frame structure 10 supported on suitable wheeled trucks in the usual manner. A conventional center sill 12 extends longitudinally of the car and is mounted for sliding movement in a longitudinal direction with respect to the car. Coupler means 14 are carried at opposite ends of the sliding center sill.

The shock absorbing mechanism of the present invention includes a cylinder 16 and a piston 18. As seen most clearly in FIGS. 2 and 3, said cylinder 16 has a fitting 20 rigidly secured to one end thereof, this fitting having a slot 22 extending therethrough which receives a transversely extending rigid key member 24.

Piston 18 includes a piston rod portion 26 having a fitting 28 rigidly aflixed to the outer end thereof. This fitting has a slot 30 formed therethrough which receives a transversely extending rigid key member 32.

As seen in FIG. 2, center sill 12 includes a first pair of fittings 40 at opposite sides thereof and a second pair of fittings 42 at op osite sides thereof spaced from fittings 40. Each of these fittings defines an elongated slot extending longitudinally of the center sill. Key 24 is adapted to slide longitudinally within the slots formed in fittings 40, and key 32 is adapted to slide longitudinally within the slots defined in fittings 42.

The adjacent frame structure 10 is provided with a first pair of fittings 44 and a second pair of fittings 46, each of fittings 44 and 46 also defining a slot extending longitudinally of the car. Key 24 is longitudinally slidable within the slots defined in fittings 44, and key 32 is mounted for longitudinal sliding movements within the slots defined in fittings 46.

The key and slot construction provides a lost motion interconnection between the cylinder and piston of the shock absorbing mechanism and the center sill and frame structure of the car.

The inner end of piston rod portion 26 of the piston carries an annular head 50 which is rigidly secured to the piston rod portion. Conventional sealing means 52 is carried by head 50 and provides a fluid tight seal with the inner periphery of cylinder 16. An annular closure 54 is carried by the outer end of the cylinder, and sealing means 56 is supported by closure 54 to provide a fluid tight seal with the piston rod portion 26.

The opposite end of the cylinder is closed by wall 69 of fitting 20. An intermediate wall portion 62 divides the cylinder into a pair of chambers 64 and 66. Chamber 64 is of substantially greater volume than chamber 66.

A hollow fitting 70 is attached to the undersurface of cylinder 16. A hole 71 provides communication between chamber 64 and the interior of fitting 70. A differential type air inlet valve 72 is provided for filling chambers 64 and 66 With fluid, and the details of this inlet valve are described hereinafter. This valve is adapted to admit fluid into the interior of fitting 70 through a hole 74 provided in one end wall 76 of the fitting.

A check valve body 80 in communication with chamber 66 is supported by fitting 70 and is disposed within a hole 81 provided in the bottom of the cylinder. A check valve ball 82 is supported in valve body 80 and is adapted to permit fluid to flow upwardly into chamber 66, but prevents reverse flow of fluid from chamber 66 in a downward direction as seen in FIG. 3. Accordingly, the check valve will permit flow of fluid from chamber 64 to chamber 66 through fitting 70, but will prevent reverse flow of fluid from chamber 66 to chamber 64.

Fitting 70 includes a tubular portion 84 of reduced size in the center part thereof, this tubular portion having a bore 86 formed longitudinally therethrough, the upper end of this bore being in communication with the interior of chamber 66.

Portion 84 is also provided with a diametrically extended bore 87 which intersects bore 86. A selectively adjustable needle valve 88 is mounted in bore 86, the upper tapered end of this needle valve being disposed adjacent bore 87.

Fluid is adapted to flow from chamber 66 to chamber 64 through bores 86 and 87, the rate of flow being controlled by needle valve 88 which serves as a metering means.

Referring now to FIG. 4, the air inlet valve 72 includes a body 90 having a first enlarged bore 92 formed therein which is in communication with a reduced bore portion 92. A plurality of small ports 94 open at one end of the bore portion 92' and at the opposite end open to a tapered threaded bore 96. Bore 96 is adapted to receive a coupling means at the end of a conduit connected with a suitable source of fluid pressure. The inlet valve can be connected to an air or gas supply, and on a typical railway car may be connected with the supply for the air brakes of the car.

The air inlet valve includes an axially slidable member 100 including an enlarged head portion 102 which is slidably received within bore 92 of body 90. An O-ring seal 104 is disposed in a groove extending peripherally around head portion 102.

Slidable member 100 also includes a reduced cylindrical portion 106 the right hand end of which is slidably received within reduced portion 92 of body 90. A plurality of O-ring seals 108 are provided in suitable grooves provided around the right-hand end of portion 106 of the slidable member.

A bore 110 extends longitudinally through slidable member 100, and an annular gasket 112 of generally L-shaped cross-sectional configuration is provided at the right hand end of the slidable member to provide a seal with respect to the adjacent portion of body 90.

A compression spring 114 is seated within bore portion 92 of body 90 and normally urges slidable member 100 to the left as seen in FIG. 4. A bleed hole 118 is provided through the wall of body and is in communication with the space which receives spring 114 to prevent a buildup of pressure in this space.

During operation of the apparatus, air or gas pressure initially flows through ports 94 in the air inlet valve and with the assistance of spring 114 urges slidable member to the left from the closed position shown in FIG. 4 to admit air through the central bore in slidable member 100 and thence through hole 74 and fitting 70 into the two chambers 64 and 66. When the pressure within the cylinder builds up to a certain magnitude, the force produced on the left-hand large end of slidable member 100 will overcome the pressure on the small right hand end of the slidable member plus the load of spring 114 thereby moving slidable member 100 to the right and closing off the air inlet valve. The valve then remains closed until the pressure in chambers 64 and 66 drops to a lower level than the pressure at which the air inlet valve was closed.

If the pressure in chambers 64 and 66 should drop to the point where the force on the large end of slidable member 100 is less than the combined force of spring 114 and force on the small end of member 100, the valve will again move to the left and gas or air will enter the shock absorber mechanism. It is apparent that additional air or gas will be introduced into the mechanism only if there is loss of pressure within the mechanism due to leakage.

When the center sill moves longitudinally of the car, the air or gas disposed within chamber 64 of the cylinder is compressed. It is apparent for example as seen in FIG. 2 that if center sill 12 moves to the left with respect to frame structure 10, the cylinder will be carried to the left while the piston will be held in the position illustrated. On the other hand, if the center sill should move to the right with respect to frame structure 10, the piston will be carried to the right while the cylinder will be held in the pisition illustrated.

As the piston moves into the cylinder compressing the air in chamber 64, the compression will be adiabatic since loss of heat is negligible during the compression cycle. Gas or air will flow from chamber 64 into chamber 66 through the check valve until the pressure in the two chambers is equalized.

When the force on the shock absorber is released, the fluid in chamber 64 will expand and fluid will flow from chamber 66 through bores 86 and 87 into chamber 64. This flow is controlled by the setting of needle valve 88. In this manner, a portion of the energy stored by compression will be released at a slowed rate, as desired. The portion of the stored energy that is subject to slow release depends entirely on the relative volumes in chambers 64 and 66 at maximum compression.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

What is claimed is:

1. A railway car comprising a frame structure, a center sill slidably supported by said frame structure, coupler means carried by said center sill, shock absorbing mechanism for cushioning movement of said center sill with respect to said frame structure, said shock absorbing mechanism including a cylinder means and a piston means slidably positioned within a first chamber in said cylinder means, a first key means operatively connected with said piston and a second key means operatively connected with said cylinder, each of said key means being interconnected with said center sill and said frame structure,

means defining a second chamber in communication with said first chamber, air disposed within said chambers, a first passage providing communication between said first and second chambers, a check valve disposed in said first passage to permit flow of fluid from said first chamber to said second chamber and preventing flow of fluid through said first passage from said second chamber to said first chamber, a second passage providing communication between said first and second chambers and permitting flow of fluid from said second chamber to said first chamber, said second passage being of substantially smaller cross-sectional dimension than said first passage, and an air inlet valve for introducing fluid into both of said chambers, said air inlet valve being connected to a source of air pressure and including means for automatically opening the valve to admit air from said source into said chambers when the pressure within the chambers drops below a predetermined pressure and for automatically closing the valve when the pressure within the chambers reaches said predetermined pressure.

2. Apparatus as defined in claim 1 wherein each of said key means has a lost motion connection with said center sill and said frame structure.

3. Apparatus as defined in claim 2 wherein said lost motion connection includes slots formed in said center sill and said frame structure, each of said keys being positioned for slidable movement within said slots.

4. Apparatus as defined in claim 1 wherein said second chamber has a volume substantially smaller than the volume of said first chamber.

5. Apparatus as defined in claim .1 wherein said second passage is of substantially smaller cross-sectional dimension than said first passage, and including adjustable metering means disposed in said second passage.

6. Apparatus as defined in claim 1 wherein said air inlet valve is of the differential type, said valve including a large area exposed to the fluid in said chambers which tends to close the valve, the valve including a small area exposed to said source of air pressure which tends to open the valve, and resilient means normally biasing the valve toward open position.

7. Apparatus as defined in claim 1 wherein each of said key means has a lost motion connection with said center sill and said frame structure, said second chamber having a volume substantially smaller than the volume of said first chamber, said second passage including adjustable metering means disposed therein, said air inlet valve comprising a differential type air inlet valve.

References Cited UNITED STATES PATENTS 1,984,144 12/1934 Laugaudin 267-65 2,833,379 5/1958 Matthews et al. 267-65 3,220,561 11/1965 Blake 213-8 3,221,898 12/1965 Pellnitz 213-8 3,406,834 10/1968 Brunt 213-8 3,414,134 12/1968 Nealis 2138 3,444,830 5/1969 Doetsch 267-65X DRAYTON E. HOFFMAN, Primary Examiner US. Cl. X.R. 267-65 

